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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
211

Development of an omni-directional weather-monitoring anemometer

Ramakrishnan, Vijay 16 December 2013 (has links)
This work presents the design, fabrication, calibration and testing of a pressure-based three-component anemometer capable of measuring accurate wind speeds in extreme weather conditions. The groundwork, at the outset, covers the development of a 12-hole omni-directional flow-velocity measurement probe capable of measuring flows up to 155° from the probe axis. The new 12-hole design is optimal in the sense that the calculation of the four unknown flow quantities, i.e., two flow angles, flow speed and static pressure, is achieved with the minimum necessary number of holes/ports on the probe tip. The fact that this design has 33% lesser number of holes compared to an earlier design, has significant implications in the instrument’s spatial resolution, frequency response as well as cost of interfacing and usage. A prototype 12-hole probe with a spherical tip diameter of 3/8 inches was fabricated and tested. Good flow prediction accuracy was obtained. Further groundwork on multi-hole probe technology was carried out, developing new methods for correcting and refining the calibration and reduction procedures. When calibrating multi-hole velocity probes in a wind-tunnel, offset (or bias) errors often exist in the recorded flow angles due to errors in aligning the traverse system exactly with the flow direction and due to the angularity of the tunnel flow itself. These offset angles are hard to quantify from direct measurements with any degree of accuracy. Although usually small (less than 0.5° in most good calibrations), these errors still need to be corrected to increase the flow measurement accuracy of the probe. In this work, a method is developed that computes offset errors in all types of multi-hole probes – from the traditional 5- and 7-hole probes to the omni-directional 18-hole probe and the nextgeneration 12-hole probe – using simply the pressure data obtained during their calibration. The algorithm doubled the measurement accuracy for most probes. Other issues related to post-processing of the pressure data from flow studies, when the multihole probe encountered unsteady and reversed flow conditions, were also examined. The design of the anemometer (herein called a Weatherprobe) builds on that of the 12- hole probe and is capable of measuring wind velocities up to ±45° to the horizontal plane and 360° around the horizontal plane. Due to the non-conventional arrangement of its pressure ports, newly developed calibration and data-reduction algorithms were used. The probe was calibrated and its measurement accuracy assessed in a calibration facility. All associated instrumentation was assembled from the ground up and ruggedized for harsh-weather applications. Field tests performed over many days next to a 3-D sonic anemometer showed good agreement in measured flow properties, thus validating the entire Weatherprobe system. This probe has widespread applications in weather monitoring, wind energy potential estimations and structural wind load evaluations.
212

Rotational and Vibrational Raman Spectroscopy for Thermochemistry Measurements in Supersonic Flames

Bayeh, Alexander C 16 December 2013 (has links)
High speed chemically reacting flows are important in a variety of aerospace applications, namely ramjets, scramjets, afterburners, and rocket exhausts. To study flame extinction under similar high Mach number conditions, we need access to thermochemistry measurements in supersonic environments. In the current work a two-stage miniaturized combustor has been designed that can produce open supersonic methane-air flames amenable to laser diagnostics. The first stage is a vitiation burner, and was inspired by well-known principles of jet combustors. We explored the salient parameters of operation experimentally, and verified flame holding computationally using a well-stirred reactor model. The second stage of the burner generates an external supersonic flame, operating in premixed and partially premixed modes. The very high Mach numbers present in the supersonic flames should provide a useful test bed for the examination of flame suppression and extinction using laser diagnostics. We also present the development of new line imaging diagnostics for thermochemistry measurements in high speed flows. A novel combination of vibrational and rotational Raman scattering is used to measure major species densities (O_2, N_2, CH_4, H_2O,CO_2, CO, & H_2) and temperature. Temperature is determined by the rotational Raman technique by comparing measured rotational spectra to simulated spectra based on the measured chemical composition. Pressure is calculated from density and temperature measurements through the ideal gas law. The independent assessment of density and temperature allows for measurements in environments where the pressure is not known a priori. In the present study we applied the diagnostics to laboratory scale supersonic air and vitiation jets, and examine the feasibility of such measurements in reacting supersonic flames. Results of full thermochemistry were obtained for the air and vitiation jets that reveal the expected structure of an under-expanded jet. Centerline traces of density, temperature, and pressure of the air jet agree well with computations, while measurements of chemical composition for the vitiation flow also agree well with predicted equilibrium values. Finally, we apply the new diagnostics to the exhaust of the developed burner, and show the first ever results for density, temperature, and pressure, as well as chemical composition in a supersonic flame.
213

Intelligence and the speed of mental processing

Lajoie, Susanne Paula. January 1980 (has links)
No description available.
214

Predicting Evacuation Time from Lecture Theatre Type Rooms

Xiang, Xiaoxing (Primo) January 2007 (has links)
The purpose of this research is to investigate the relationships between the movement time, travel speed and occupant density during trial evacuations, particularly for theatre-type rooms. The study mainly focuses on crowd movement behaviour within a restricted space and covers aspects of human behaviour and issues needed to be considered in terms of the characteristics of lecture theatres. A set of experiments were carried out in three building blocks at the University of Canterbury in order to obtain the actual data for analysis. The number of students evacuating from each exit and the evacuation time were recorded, and their movement behaviour was monitored by video camera. Based on the experimental data, a numerical analysis was undertaken to formulate an equation for the prediction of evacuation time applying to lecture theatres. The developed equation was compared with other available relationships from the literature. An evacuation model under development, named EvacuatioNZ, was applied to simulate the experiments and the results were compared with the experimental data. The comparison showed that the developed equation showed a better performance in predicting evacuation time of lecture theatres than other available methods however, had some limitations. The EvauctioNZ model was able to be improved by using an alternative geometry input but was still not as accurate as the developed method. A recommended modification of the model was presented for improvement.
215

Anthropometric and Physical Positional Differences in International Level Female Sevens Athletes

Agar-Newman, Dana 04 December 2014 (has links)
The purpose of this study was to profile international level female sevens athletes and determine if anthropometric and physical qualities are able to differentiate between backs and forwards. Twenty-four subjects with a mean (±SD) age of 22.75±3.99 years and body weight of 69.36±5.21kg were sampled from the national team training program. Anthropometric measures (height, body mass and sum of 7 skinfolds) and performance measures (power clean, front squat, bench press, neutral grip pull up, 40m sprint and 1600m run) were collected across the 2013-2014 centralized period and compared across playing position. Thirteen backs (mean age±SD= 21.28±3.54 years) and eleven forwards (mean age±SD= 24.47±3.95 years) had significant differences in body mass (66.40±3.48kg vs. 72.87±4.79kg) and initial sprint momentum (366.81±19.83kg*m/s vs.399.24±22.42*m/s). However no other measures showed positional differences. It is possible that the lack of positional differences in female rugby sevens is due to the multifarious physical requirements of a sevens player, leading to a generic player profile or perhaps due to a lack of selective pressure. It is also possible that the anthropometric and physical qualities measured in this study lacked the necessary resolution or failed to capture the unique attributes of each position. In conclusion, this is the first research profiling international level female sevens athletes. The normative data presented within this paper highlights the physical requirements of female sevens athletes for strength and conditioning practitioners. In addition, the lack of positional differences discovered should impact training program design. / Graduate
216

Quantification of the effects of non-motorised transport and roadside activities

Bari, Md Mahabubul January 1999 (has links)
No description available.
217

Modelling, testing and design of a surface piercing propeller drive

Dyson, Peter Kevin January 2000 (has links)
No description available.
218

Design and control of a synchronous reluctance machine drive

Sharaf-Eldin, Thanaa January 1999 (has links)
No description available.
219

An improved design of wind towers for wind induced natural ventilation

Al-Qahtani, Turki Haif January 2000 (has links)
No description available.
220

A methodology for evaluating fleet implications of mission specification changes

Brett, Paul S. 12 January 2015 (has links)
Civil aviation has matured to become a vital piece of the global economy, providing the rapid movement of goods and people to all regions. This has already led to significant growth and expectations of further growth are on the rate of 5% per year. Given the high projected rate of growth, environmental consequences of commercial aviation are expected to rise. To mitigate the increase of noise and emissions, governing bodies such as ICAO and the FAA have established and are considering additional regulation of noise, NOₓ, and CO₂ while the European Union has integrated aviation into their Environmental Trading Scheme. The traditional response to new regulation is to integrate technologies into the aircraft to reduce environmental footprint. While these benefits are positive on the aircraft level, fleet growth is projected to outpace benefits provided by technology alone. To further reduce environmental footprint, a number of mitigation strategies are being explored to determine the impact. One of those strategies involves changing the mission specifications of today's aircraft by reducing range, speed, or payload in an effort to reduce fuel consumption and has been predominantly focused at the vehicle level. This research proposes an approach that evaluates mission specification changes from the aircraft design level up to the fleet level, forecasted into the future, to assess the impact over a number of metrics to fully understand the implications of mission specification changes. The methodology Mission Specifications and Fleet Implications Technique (MS-FIT) identifies stakeholder requirements that will be tracked at either the vehicle or fleet level and leverages them to build an environment that will allow joint evaluation to facilitate increased knowledge about the full implications of mission specification adoption. Additionally laid out is an approach on how to select prospective routes for intermediate stops based on fuel burn and operating cost considerations. Guidance is provided on how to filter down a list of candidate airports to those most viable as well as regions of the world most likely to benefit from intermediate stops. Three sample problems were used to demonstrate the viability of MS-FIT: cruise speed reduction, design mission range reduction, and the combination of speed and range reduction. Each problem was able to demonstrate different implications from the implementation of the different specification changes. Speed reduction can negatively impacts cost while range reduction has consequences to noise at the intermediate airports. The combination of the two draws in negative implications from both even though the environmental benefits are better. Finally, an analysis of some of the assumptions was conducted to examine the sensitivity to the results of speed and range reduction. These include variation in costs, reductions in annual utilization of aircraft, and variation in intermediate stop adoption. Speed reduction is strongly sensitive to increases in crew and maintenance rates while landing fees significantly eat into the benefits of range reduction and intermediate stops. Minor utilization reductions can significantly reduce the viability of speed reduction as the increase in capital costs offset all the savings from fuel reduction while range reduction is a little less sensitive. Intermediate stop variation does not eliminate the benefits of range reduction and even can provide cost savings depending on the design range of the reduced variant but it can have consequences to airport noise to higher traffic airports. With the proposed framework, additional information is available to fully understand the implications with respect to fuel burn, NOₓ emissions, operating cost, capital cost, noise, and safety. This can then inform decision makers on whether pursuing a particular mission specification strategy is advantageous or not.

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